Abstract

The most common gas lift design procedure used currently is a calculation of gas lift valve parameters (PTRO & port size) based on an approximation approach using a static model. To enhance a gas lift design, a gas lift simulation based on both static and dynamic models has been developed in ARII's gas lift operations.

This paper details the construction of gas lift simulation using a computer spread sheet program and its applications in fine-tuning and testing gas lift designs with casing operated valves.

The most critical step in the gas lift simulation is the prediction of injection gas passage through a gas lift valve port at various tubing (Pt) and casing pressures (Pc). This performance may be obtained from gaslift manufacturers based on the actual passage performance test. Due to the limitation of this data, the authors tried to predict the injection gas passage performance using semi-empirical equations based on static and dynamic models.

The other benefits of a gas lift simulation are to help production engineers in gas lift optimization and trouble shooting analysis; such as, identifying leaking valves/tubing, malfunctioned valves, and fundamental problems i.e. mandrel spacing that does not match the well performance.

The authors also tried to compare the flow performance predicted in this paper with the actual performance measured during test by a gas lift manufacturer (see Table 1).